1. Field of the Invention
This invention concerns S-substituted phenyl, N,N-alkenyl and halogen substituted alkyl thiolcarbamates, in particular, S-p-methoxyphenyl, N,N-diallylthiolcarbamate and S-p-methoxyphenyl N,N-bis(2,3-dibromopropyl)thiolcarbamate. This invention also concerns the method of controlling the deleterious effects of nematodes upon plants, particularly by systemic control.
2. Description of the Prior Art
Nematodes (nemas) attack plants (trees, shrubs, etc.) and plant parts such as stems, roots, and bulbs causing deleterious effects by weakening the plant, decreasing the yield of fruit, stunting its growth, or causing lesions through which other parasitic organisms enter and harm the plant.
One method of combatting nematodes living in the soil, or upon decaying vegetation is to rotate the crops, but this is ineffective when the plants are maturing. Another methd is to use soil fungicides which kill nematodes, particularly those living in the soil, so as to rid the soil of these nematodes prior to crop planting. Examples of soil fungicides are methyl bromide, and chloropicrin. Soil fungicides are expensive, and in many cases are phytotoxic to plants. Another method is to apply nematocides to soil or to the bulbs to kill the nematodes prior to their entering the plant. Many nematodes, however, attack plants or become embedded within plants prior to application of the nematocide, or after the effective life of the nematocide, and these nematodes are not affected by such applications of nematocides. Another method is to apply systemic nematocides, which are applied to the plant; e.g., the foliage of the plant, to systemically control the deleterious effect of nematodes on the plant. This systemic control may result either from one or several different mechanisms. It may result from a translocation of the compound (or a metabolite thereof) from its application site (e.g., the foliage) to the area deleteriously affected by nematodes (the roots) where it controls the deleterious effect, e.g., by killing the nematodes or repelling them from the area, or by inducing rapid healing of the plant wound caused by the nematode. It may result from a translocation of the compound (or a metabolite thereof) from the application site (foliage) through the plant to outside the area deleteriously affected by nematodes (e.g., the roots), where it provides a protective shield against nematodes, such as a root coating which repels or kills nematodes feeding upon this area of the plant. It may result from the translocation of the compound or a metabolite thereof from its application site into the enzyme system of the plant where it stimulates formation of chemicals which repel or kill the nematodes attacking the plant or which rapidly heal the wounds caused by the nematodes.
Many thiolcarbamates are known as herbicides, fungicides, or nematocides, but very few are systemic nematocides. U.S. Pat. Nos. 2,977,209 and 3,265,563 disclose S-phenyl N-alkyl thiolcarbamates, S-chlorophenyl N-alkyl thiolcarbamates, S-ethoxy N-allylthiolcarbamate, and S-ethoxy N-alkyl thiol carbamates as herbicides and fungicides. U.S. Pat. Nos. 2,992,091 and 3,144,475 disclose S-substituted benzyl N,N-dialkylthiocarbamates and dithiocarbamates and defoliants and herbicides. U.S. Pat. No. 3,632,332 discloses S-4-methylbenzyl-N,N-diethylthiocarbamate as a herbicide for rice fields. U.S. Pat. No. 3,301,885 discloses S-substituted phenyl N-alkyl, N-alkoxy thiolcarbamates as herbicides, miticides, and insecticides. U.S. Pat. No. 3,687,653 discloses trifluoromethylbenzyl N-alkyl thiolcarbamates as herbicides. U.S. Pat. No. 3,046,189 and Canadian Pat. No. 789,575 discloses S-alkyl N-alkylthiocarbamates as nematocides.